A normal oxygen level, as determined through oximetry, is between 95 and 100 percent, UCSF Medical Center reports. A normal arterial oxygen pressure for an arterial blood gas study is 80 to 100 mmHg.
Both the oximetry test and the arterial blood gas study determine the amount of oxygen saturation present in hemoglobin at the time of the test, according to WebMD.
Oximetry utilizes a device that is put on the tip of a finger, explains UCSF Medical Center. It uses two light sources, one red and one infrared, that transmit through the tissues to a detector on the other side. The amount of light absorbed by the hemoglobin allows the oximeter to calculate the oxygen level in the blood.